| 摘要 |
PURPOSE:To make it possible to determine immediately from the appearance whether a battery having an effective voltage is set in a camera, by a system wherein a battery check circuit connected to the main source battery is made to start periodically by a time count circuit. CONSTITUTION:When size AA dry cells 7 are set correct in terms of polarity, first a microcomputer 4 for LCD measures an open-circuit voltage VB to conduct a very rough battery check as to whether the voltage is 1.5V or above, as a means to detect the presence of the battery. Although this check is conducted every second by a time count circuit of the microcomputer 4, the current of the size AA dry battery 7 is not consumed since the open-circuit voltage is measured. When the check shows that the voltage is 1.5V or above, the time count circuit executes an integration for a prescribed time and starts a booster circuit 1 and a microcomputer 2 for control through the intermediary of a starting transistor 6. The microcomputer 2 controls a driver circuit 3 to make a constant current flow through a motor M, and during this control, transfers the result of measurement of a voltage V'B to the microcomputer 4 so that the voltage level thereof be displayed on LCD 5. Although the precision of detection in this case is very high, the level is classified into three patterns, for instance, for practical use and displayed.
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